She advised card holders to check with their banks if they had concerns.

ANZ, ASB and BNZ also offer payWave cards. ASB and BNZ send out unactivated cards which require the customer to make a further step after receiving the card in the mail.

An ANZ spokesman said any customers with concerns could opt to pick up a card from the bank.

Consumer NZ finance writer Kate Sluka said she was surprised TSB was sending out pre-activated cards. Theft from letterboxes was no different from the "old-style credit cards" where someone could have gone on an online spending spree, she said.

It was a risky move on TSB's part and unnecessary since other banks send cards unactivated, she added.